Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New record for measurement of atomic lifetime

08.09.2011
Researchers at the Niels Bohr Institute have measured the lifetime of an extremely stable energy level of magnesium atoms with great precision.

Magnesium atoms are used in research with ultra-precise atomic clocks. The new measurements show a lifetime of 2050 seconds, which corresponds to approximately ½ hour. This is the longest lifetime ever measured in a laboratory. The results have been published in the scientific journal Physical Review Letters.

The experiment consists of magnesium atoms which are captured using laser light in a so-called magneto-optical trap and cooled to near absolute zero, minus 273 degrees Celsius. Then the atoms are energized with laser light, which causes the electrons to jump from their ground state into a higher energy level. This higher energy level is called an excited state, but this state is usually very unstable and normally decays within a few nanoseconds. However, some special states may live much longer, up to several seconds or more before they decay, and are therefore called metastable states.

Extremely long lifetime

"Some atoms are easy to manipulate, while others are more difficult to get to jump into an excited state and the harder it is to get them to jump, the longer they last. We have been working with the magnesium-24 isotope, which is the most common form of magnesium. This atom has a metastable state, which is very difficult to excite, but using a special technique we have been able to transfer the magnesium atoms to the metastable state and measure a lifetime for this state of 2050 seconds. This is an extremely long lifetime", explains atomic physicist Philip G. Westergaard, who as part of the research group under the leadership of Jan W. Thomsen at the Niels Bohr Institute is working towards developing an atomic clock based on ultra-cold magnesium atoms.

To be more precise, the measurement revolves around the lifetime of the quantum mechanical state of two electrons in the third electronic shell for magnesium-24. In order to perform the lifetime measurement, up to 108 (hundred million) magnesium atoms are captured and cooled using laser light in a magneto-optical trap. Then the atoms are excited to the metastable state and transferred to a magnetic trap, where the lifetime can be measured.

In order to rule out systematic effects on the measured value, several sources of errors were measured. This included cooling the entire experiment down to below 0 degrees Celsius using dry ice, though without it affecting the result. The final uncertainty of the result was 5.5 %, which is a rather small uncertainty for this type of measurement. This means that the measurement can be used to verify theoretical predictions in quantum physics and help to make more accurate theoretical models of multi-electron systems.

Extremely accurate atomic clock

The long lifetime of the excited state of the magnesium atoms will have an impact on the advancement of ultra-precise atomic clocks, which the research group at the Niels Bohr Institute is working to develop.

The atomic clock consists of a gas of magnesium atoms, which is held in a trap using laser light and magnetic fields and cooled down to minus 273 degrees C. In this state the researchers can exploit the quantum properties of the atoms and get them to function like a clock with a pendulum. The electrons of the atoms move in fixed orbits around the nucleus and using ultra-stable laser light you can get the electrons to jump back and forth between these orbits, and this is what constitutes the pendulum in the atomic clock.

"Our new results with keeping the atoms in the excited state for a very long time give us better control of the electrons jumping between orbits and this means that the quantum uncertainty is reduced. This can be used to develop an atomic clock that is so accurate that it only loses one second per 900 million years", explains Jan W. Thomsen.

Ultra-precise atomic clocks can be used to verify Einstein's general theory of relativity as well as test whether constants of nature change over time, for example, the fine structure constant, which describes the size of the electron energies of the atomic structure. In addition, atomic clocks can be used for navigation, for example for GPS, and high-speed telecommunications.

Contact:

Jan W. Thomsen, Associate Professor, Ultra Cold Atoms and Quantum Optic, Niels Bohr Institute, University of Copenhagen, +45 3532-0463, +45 6131-1865, jwt@fys.ku.dk

Philip G. Westergaard, Postdoc, Ultra Cold Atoms and Quantum Optic, Niels Bohr Institute, University of Copenhagen, +45 3532-0504, mob: +45 4162-1773, pgw@fys.ku.dk

Physical Review Letters: Reference is volume 107, page number 113001 http://prl.aps.org/toc/PRL/v107/i11

Gertie Skaarup | EurekAlert!
Further information:
http://www.nbi.dk

Further reports about: Atoms Letters Optic Quantum Ultra atomic clock cold fusion laser light magnetic field

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>